1. Field of the Invention
The present invention relates to unicondylar or partial knee arthroplasty, specifically the invention relates to a femoral component used during such an operation.
2. Description of the Related Art
Total knee arthroplasty (xe2x80x9cTKAxe2x80x9d) has long been a successful treatment for patients who have knee joints that have been damaged by disease or trauma. During a TKA a patient""s damaged knee is replaced with an endoprosthetic implant generally comprising a femoral component, a bearing component, and a tibial component wherein the femoral component is attached to the distal femur of the patient. This fixation occurs in part via a clamping force against the distal femur generated between the posterior and anterior flanges of the femoral component. Femoral components used during a TKA may further comprise a porous surface that promotes growth of bone into the implant. Such boney ingrowth provides better fixation of the implant and for a more accurate simulation of a natural knee.
Sometimes, however, a patient""s knee is only partially damaged, thus it is sometimes only necessary to fix one compartment, or condyle, of the damaged knee. It is desirable in such circumstances to form a partial knee arthroplasty (xe2x80x9cPKAxe2x80x9d) which normally requires less surgical cutting and therefore less trauma to the patient. Unfortunately, unicondylar femoral components do not have posterior flanges with which the anterior flange can generate a clamping force against a distal femur. It is desirable, therefore, to provide a unicondylar femoral component for a PKA that may be attached to a distal femur despite lacking a posterior flange. It is further desirable to provide a unicondylar femoral component for a PKA that comprises a porous surface useful in promoting boney ingrowth.
A unicondylar femoral component for use in a PKA according to the present invention comprises, in one embodiment thereof, an articulating surface, a bone contacting surface, a posterior post, a porous layer, and an anterior flange. The post and flange are disposed such that a clamping force is generated there between against a prepared distal femur thereby holding the implant in place.
In a second embodiment, the present invention comprises an articulating surface, a bone contacting surface, a posterior post, an anterior post, and a porous layer wherein the clamping force against the distal femur is generated between the posterior and anterior posts.
In a third embodiment, the unicondylar femoral component of the present invention comprises an articular surface, a bone contacting surface, a porous layer disposed on the bone contacting surface and at least two threaded fasteners that are threaded through the femoral component and into the distal femur.
It is an advantage of the present invention that it allows a unicondylar femoral component to be fixedly attached to a distal femur.
Another advantage of the present invention is that it accommodates a porous layer disposed on the bone contacting surface of the femoral component.
Another advantage of the present invention is that it allows for the use of a trabecular metal porous layer.
Other advantages and features of the present invention will be apparent to those skilled in the art upon a review of the appended claims and drawings.